The present invention relates to a method and a device for the measuring of the level of a fluid inside of a container.
Several methods and devices for so measuring the level of a fluid are known in the art. For example, it is well known that one may use a vibration probe, sense the position of a float, or measure the difference in pressure of the fluid that is entering and exiting the container. With these measuring methods, however, at least part of the measuring device must be in direct contact with the fluid inside of the container. This feature of the presently available methods and devices can be a great disadvantage if, for example, the fluid being measured is radioactive. Such a circumstance provides an obvious hazard when the device must be serviced while it remains in the radiation field.
Therefore, the so-called "bubble-injection method" may be used to avoid this disadvantage. This method utilizes the principle that the pressure applied at an injection point in order to introduce air bubbles is dependent upon the amount of liquid above the injection point. Such a method, however, may require the continuous injection of air. For many applications, such as a reconditioning plant, this is undesirable. First, an air supply apparatus must be used, along with considerable instrumentation for air production. Air must be supplied at the correct rate and the pressure signal must be converted into a suitable (electric) indicator signal. Moreover, the addition of air, in many applications, results in an aerosol formation. As a result, the exhaust air filters are encumbered.
The present invention therefore provides a novel method for measuring the fluid level in containers. The method of the present invention is more simple to carry out than previously known methods. In particular, it may be used advantageously in measuring the level of radioactive fluids in containers. Furthermore, a suitable device is provided to carry out the method.